Conversion process



UNIT-Eu STATE Patented June 18, 12935 CNVERSIQN PROCESS 'VanderveerVoorhees, Hammond. Ind., assignor to Standard Oil Company, Whiting,Ind., a f

corporation of Indiana Application February 14,

.5 claims. V(c1. 19t-4s) f The present invention relates toimprovements' in the production of lower boiling point hydrocarbon oilssuch as gasoline or other oil suitable as ,the numeral 5 indicates afurnace, in'which there isprovided a' suitable l'heating coil forAimparting a desired cracking temperature to the oil under treatment.The oil issupplied to, the'coil in the 'furnace through the line 6 bythe pump 'L'jand after being heated, leaves the furnace through the lineIa provided with a pressure release valve 3. The oil or vapors then passthrough the line 3 into a manifold I0, from which the oil maybeldischarged at a-selectedlev'el through line .line l2 or line I3, intothe enlarged chamber Il.

The latter is preferably of a vertically elongatedform and is'providedat its bottom with a suitable .manhead.|5, permitting access' to itsinte? rior for cleaning and removal of coke.

vapors pass out'of, the 'enlarged chamber I4 through'the line I6provided'with valve I'Land enterA thelower portion of the tower I3.Theinterior of vthis tower is provided with suitable fractionatingplates I3, such as baille plates or scen plates and in the upper portionthereof, 'a few' more emcient fractionating plates 20, such 'as bubblecap plates, maybe arranged. Oil may be discharged into this tower atoneor more levels through the pipes 2 Il, 2 Ib, `2 Ic, 2 Id, which aresupplied from the manifold 22. Oil thus supplied descends the tower'incountercu'rrent to the rising vapors, scrubs the latter,V and theresulting liquid visc'ollected in the lower portionv of the tower I6'.This liquid is removed from the tower I6 through the discharge line 23by pump 24. It

' is then r'forced to the line 25, and a 'part 4of or all of it may becaused. to pass through the valved line 26 into the'line 3 before itenters the mani- .fold I6. Any remainder of oiliwithdrwn from the baseof the columnl may be discharged from the system through the valved line`2I.

This line may also be employed for supplying additional oil to the line26, when desired for pur-V poses' of temperature control. lF'or oil sosupplied' it is preferred to use residual oils, which could..

`not otherwise be distilled without deposition of cok'e.

'1930, serial No; 428,398'

pass out 'through the vaporline 23 into an intermediate point in thefractionating -tower 23, which is suitably provided internallyl withfractionating. plates 30, illustrated as bubble cap! plates. The upperportion of the column may be cooled, for example, -by oil fed to thecoil 3| in the top of the column from the oil vsupply line 32. By thismeans, a suitable reflux is es-v tablished in the column,` and. the oilpassed through the coil 3| is preheated. This oil is disl0 charged fromthe coil 3| through theline 32,

by vwhich in is conducted tu the une as leading -to the suction side ofpump -1 which feeds line 6 and the heating coil in furnacefli. A by-pass32b'is provided` around coil 3|.

`Condensatie formedin the column 29 descends and vcollects in the. lowerportion ofthe column, where it may be stripped, if desired, by steamsupplied from line 34 to the distributing -pipe 35 in' the lower portionof the column.- The congo densate leaves the column through the line 36.

A portion of it may be taken up through valved line 3l by the pump 33and fed to the manifold 22, from which it may be caused to enter thecolumn I3 through the lines 2|, 2lb, 2|c and r2| g5 at one or moredesired levels. The remainder of the oil or condensate withdrawn fromthe lower portion of the column 29 passes through the valved pipe 39 tothe line 33 leading to the pump 'I which passes it. together with theoil preheated 30 in the coil 3|, into' the heating coil in the vfurnace.

The following illustrates a process conducted .in accordance with theypresent invention.

.-A suitable heavy oil, whichit 'is desired to 35 convert into-`gasoline, and which is preferably a distillate oil heavier thangasoline, is supplied by pump or other suitable device to the line 32and is passed throughthe coil 3| 'in the 'upper portion of theAfractionating column 26, 40

beingthere preheated by the rising vaporsy and cooling the lattertoprovide condensate and reilux. Thefoil, thus preheated.' passesthrough line 32a and mingles with the condensate which collects in thelower. portion of the column 23 '45 and which passes out of the latterthrough the` lines 36 and 33. The mixedoil, whichis at a temperaturebelow' that at which cracking 'to form gasoline takes place at anappreciable rate, is forced by pump.y 'l through lin'e6 finto 460 the'heating coill in furnacei. l In the latter, the

oil is heated `to completely vaporize it vand bring the vapors to arapid-cracking temperature.

1 AlthoughV any desired vaporphase cracking` conditions vmay. beemployed in heating the oil 55.

-in the heating coil, it is preferred to cause it to -be rapidlyvaporized pointed out -cracking and coking temperature therein matter..The heavy outy through the line and brought to' a temperature of atleast 850 F. with a relatively small amount of cracking to gasoline;preferably not more than 15% of the total amount of cracking to gasolineduring the entire pass. In its continued travel through the heatingcoil, the oil vapors are maintained at a temperature above 850 F., andpreferably brought to a temperature of 900 to 1000o F. with a pressureon the coil outlet of 100 to 400 lbs., maintained by the valve 8.Although such conditions are preferred, as they produce a desirable typeof fuel product of the vapor phase type with relatively low loss, as inthe Snow and Sullivan Patent 1,918,991, and other desired conditions forthe production of vapor phase or liquid phasecracking, as preferred, maybe employed. As will be apparent hereinafter, the temperature V,employedmust be sufficiently high to effect the desired of the heavy tarryproducts introduced through the line 26, and must be substantially abovethe minimum (say by 50 to 100 F.) required -to secure the desired typeof cracking.

InV passing through the valve 8, the pressure onthe hot oil vapors oroil products from the heating coil is reduced, say'to l0 to 60 lbs.gauge, or even to substantially atmospheric. The oil then passes throughthe line 9 to the manifold.

coke by their contained heat. In beginning operations, the chamber I4may be preheated, for example, by the procedure described in the ThielePatent 1,947,319. The oil products may be initially introduced from themanifold I0 through the lower pipe II. chamber I4 builds up, the line IImay be closed and the oil products then introduced through the higherline I2. AOn further building up of the coke deposit in the o be closedoff also, and the oil products allowed to enter through the line I3. Itis preferred to employ a plurality of chambers such as chamber I4, whichmay be used alternately or in rotation as each is lled with coke. Forsimplicity of illustration, only one is shown.

The vapors from the chamber I4 pass out through the linejl. Coking orclogging of the outlet of the chamber may be avoidedv by supplyingthereto a small amount of fresh oil, as through line 4I and'nozzle 42directed' towards the opening of vapor line I8. The chamber I4 willordinarily beat a temperature of 850 F. or higher, and 'may be somaintained by lagging or by the application of a mild-heat. A suitableis about 900"- F. The vapors coming off may be at 'a temperature of 800F. or

higher, say 800,to 850 F. These'vapors pass into,

the scrubbing tower I8, wherein they are scrubbed with a smallproportion of oil introduced into oneor more of the pipes 2 Il, 2 Ib, 2Ie, 2ld at different levels to remove entrained heavy or tarry productsthus entrained, together with the feed stock supplied into the tower I8,collect in the bottom of the latter and pass -23 to Athe pump 24, whichforces them to the line 25 and the line 28 into vtop of the column.

As the coke deposit in the chamber I4, the line I2 may,

'the enlarged chamber completely to coke or to a non-liquid residuum.

the line 9, conveying the hot vapors and oil products from the heatingcoil to the enlarged chamber I4. If the proportion of heavy productsthus supplied to the line 9 is excessive, sothat satisfactory reductionand conversion to coke does not take place in the enlarged chamber I4, aportion o f such heavy products maybe diverted through the line 21' tostorage or 'used as fuel oil. The proportionof heavy Aproducts which maybe then added to the hot vapors passing through the line 9 will notordinarily-exceed about 10%. The vapors fromthe scrubbing tower I8 passout through the vapor line 28 into the fractionating column 29, in whichthe heavier portions thereof, heavier than the desired gasoline product,are condensed, suitable cooling being effected byA the passage ofsuitably controlled proportions or all of the fresh oil throughthe coil3I in the the vapors,` including the hydrocarbons in the gasoline pointrange, pass out 43 to the condenser 44.

vThe refluxcondensate formed in the Vcolumn ,29, which may be completelystripped of its lighter constituents by steam supplied to thedistributing pipe 35 from the line 34, `passes out through the line 36,and a portion thereof is withdrawn through the line 31 by the pump 38 tobe forced into the manifold 22, from which it passes into the scrubbingtower I9. The remainder of the condensate formedin the column 29 mixes.with the preheated fresh oil. If desired, instead of condensate fromtower 29, fresh oil may be drawn by pump 38 from line 32a through line4.0 and fed to the scrubbing tower I9.

Although 'it is preferred to maintain vapor phase crackingconditions inthe heating coil, suitable temperatures and pressures may be employed,as is well knownfin the art, to retain a part or all of the oil in theliquid phase at the outlet thereof. The pressure conditions in the coil,which may be at 100 to 1000 lbs. pressure or higher, and the supply ofheavy oil products to The lighter constituents of .2.0

through the linev the products from the heating coil as they enter lareso controlled as to sev In the event thatany liquid residuum collectse therein, it may be kept at a high temperature so as to besubstantially completely converted into a solid residuum or coke vbycausing apart or all of the highly heated products from the heating coilto enter the enlarged chamber through a lower. inlet.

The proportion of tarry liquid scrubbed out of the vapors`from thechamber I4 in the tower I8 is relatively small, and the productssoremo'ved are of a tarry nature unsuitable of itself as a crackingstock'.- Atmospheric pressure or pressure only slightly higher, say notmore than 2 5 to 30 lbs.,is preferably maintained. inthescrubbin'g'tower Il. The fractionating plates or baille plates employedin the lower portion thereof are preferablyI` of a character suc'h asbaffle plates, 4which may be readily cleaned of accumulations of cke `orcarbonaceous material.

I' claim: `1. The method of boiling hydrocarbon oils into lowerboiling'products such as gasoline which comprises' heating in a confinedstream a substantially comlpetelyvaporizable hydrocarbon oil chargingstock con sisting substantially entirely of a petroleum distillate tosubstantially completely vaporize the oil and bring the vapors to a highcracking temperature-of at least 900 F., passing the stream of heatedoil vapors into an enlarged chamber wherein they undergo substantialcracking in the .vapor phase by their contained heat, removing in astream the cracked vapors from said chamber and passing the stream ofvapors directly to and through a scrubbing tower, continuouslyintroducing into said tower a small proportion of the said vaporizablecharging distillate stock supplied to the cracking operation andintimately contacting the said vapors owing through said tower only withsaid completely vaporizable distillate charging stock which is added ina volume just suilicient to scrub from the said cracked vaporssubstantially only entrained heavyand tarry products of cracking,passing only liquid products comprising said heavy tarry products fromsaid tower into said enlarged chamber while excluding from said chamberheavy residual stocks from external sources, and

intimately contacting them with the aforesaid stream of highly heatedoil vapors entering the said enlarged chamber, retaining the said heavyproducts in said chamber at a cracking temperature until they aresubstantially completely converted to solid residuum, separatelywithdrawing the scrubbed vapors from said scrubbing tower and passingthem directly to a fractionating operation wherein undesired higherboiling constituents thereof are separated in the form of refluxcondensate, and separately removing and collecting the fractionatedvapors.

2. The method of converting relatively high boiling hydrocarbon oilsinto lower boiling products such as gasoline which comprises heating inf a. confined stream a substantially completely va- 40` porizablehydrocarbon oil charging stock consisting substantially entirely of apetroleum distillate to substantially completely vaporize the oil andbring the vapors to a high cracking temperature, passing the stream ofheated oil vapors into an enlarged chamber wherein they undergosubstantial cracking in thevapor phase by their contained heat, removingin a stream the cracked vapors from said chamber and passing the streamof vapors directly to and through Aa scrubbing tower, continuouslyintroducing Vinto said tower a small proportion of the said vaporizablecharging distillate stock supplied, to the cracking operation andintimately contacting the said vapors owing through said Atower onlywith said completely vaporizable distillate charging stock which isadded inv volume just suflicient to scrub from the said cracked vaporssubstantially only entrained heavy and tarry products of cracking,passing only liquid products comprising said heavy tarry products fromsaid tower into said enlarged chamber while excluding from said chamberheavy residual stocks from external sources, and intimately contactingthem with the aforesaid stream of highly heated oil vapors entering thesaid enlarged chamber, ,the proportion of r the returned heavy productsbeing not above relative to thetotal material charged to said lenlargedchamber, retaining the said heavy products in said chamber at a crackingvtemperature until they are substantially completely converted to solidresiduum separately withdrawing the scrubbed vapors from said scrubbingtower and passing them directly to a fractionating operation whereinundesired higher boiling constituents theref are separated in the formof reaooaiis ux condensate, and separately removing and collecting thefractionated vapors.

3. The method of converting relatively high boiling hydrocarbon oilsinto lower boiling products such as gasoline which comprises heating ina confined stream a substantially completely vaporizable hydrocarbon oilcharging stock c'onsisting substantially entirely of a petroleumdistillate to substantially completely vaporize the oil and bring thevapors to a high cracking temperature, passing the stream Aof heated oilvapors in'to an enlarged chamber wherein they undergo substantialcracking in the vapor phase by their contained heat, removing in astream the cracked vapors from said chamber and passing the -stream ofvapors directly to and through a scrubbing tower, continuouslyintroducing into said tower a small proportion of the said vaporizabiecharging distillate stock supplied to the cracking operation andintimately contacting the saidvapors fiowing through said tower* onlywith `said completely vaporizable distillate charging stock which isadded in volume just suicient to scrub from the said cracked vaporssubstantially only entrained heavy and tarry products of cracking,passing only liquid products comprising said heavy tarry products fromsaid tower into said enlarged chamber while excluding from said chamberheavy residual stocks from external sources, and introducing them intoand intimately contacting them with the aforesaid stream of highlyheated oil vapors entering the said enlarged chamber, retaining the saidheavy products in said chamber at a cracking temperature until they aresubstantially completely converted to solid residuum, separatelywithdrawing the scrubbed vapors from said scrubbing tower and passingthem directly to a fractionating operation wherein undesired higherboiling constituents thereof are separated in the form of reiluxcondensate, withdrawing said condensate and passing it to the saidheating and vaporizing operation as charging stock therefor, andseparately removing and collecting the iractionated vapors.

4. The method of converting relatively high boiling hydrocarbon oilsinto lower boiling products such as gasoline which comprises heating ina confined stream a substantially completely vaporizable hydrocarbon oilcharging stock consisting substantially entirely of a petroleumdistillate to substantially completely vaporize the oil and bringthevapors to a high cracking temperature of at least 900 F., passing thestream of heated oil vapors into an enlarged chamberv wherein theyundergo substantial cracking in the vapor phase by their contained heat,removing in a stream the cracked vapors from said chamber` and passingthe stream of vapors directly to and through af scrubbing tower,continuously inl troducing into said tower a small proportion of thesaid vaporizable charging distillate stock supplied to the crackingoperation and intimately contacting the said vapors flowing through saidtower only with said completely vaporzable distillate charging stockwhich is added in volume just suflicient to scrub from the said crackedvapors substantially only entrained heavy and tar ry products ofcracking, passing only liquid products comprising said heavy tarryproducts from said tower into said enlarged chamber while excluding fromsaid chamber heavy residual stocks from external sources, andintroducing them into and intimately contacting them with the aforesaidstream of highly heated oil vapors entering the said enlarged chamber,the proportion of the returned heavy products being not above 10%relative to the total material charged to said enlarged chamber,`retaining the said heavy products in said chamber at a crackingtemperature until they are substantially completely converted to solidresiduum, separately withdrawing the scrubbed vapors from said scrubbingtower and passing them directly to a fractionating operation whereinundesired higher boiling constituents thereof are separated in the formof reflux condensatawithdrawingv said 'condensate and passing it to the4saicl heating and vaporizing operation 'as charging stock therefor, andseparately l a confined stream a substantially completely vaporizablehydrocarbon oil charging stock consisting substantially entirely of apetroleum distillate to substantially completely vaporize the oil andbring the vapors to a high cracking temperature, passing the stream ofheated oil vapors into an 1 enlarged chamber wherein they undergosubstantial cracking in the vapor phase by theirl ccnthe saidvaporizable charg ng distillate stock supv plied to the crackingoperation and intimately contacting the said vapors flowing through saidtower only with said completely vaporizable distillate charging stock toscrub from the said cracked vapors substantially only entrained heavyand tarry products of cracking, separately withs -drawing the saidscrubbed heavy tarry products and introducing them into the stream ofhighly heated vapors at a point intermediate the said heating operationand the said`enlarged chamber, retaining the said heavy products in saidchamber at a cracking temperature until they are subin the form ofreflux condensate, and separately i removing and collecting thefractionated vapors.

VANDERVEER VOORHEES.

